Syrian president Bashar al-Assad warned Monday that European powers would "pay the price" if they sent weapons to rebel forces seeking to topple him.

"If the Europeans deliver weapons, then Europe's backyard will become terrorist, and Europe will pay the price for it,"
he was quoted as saying by German daily Frankfurter Allgemeine Zeitung.

Sending weapons to rebels would lead to terrorism in Europe, he said according to an interview to appear in Tuesday's edition of the newspaper.

"Terrorists will return, battle-hardened and with an extremist ideology," he was quoted as saying.

Assad pointed to one rebel faction, the Nusra Front, and said: "It represents the same ideology" as al-Qaeda and "aims to establish an Islamic state."

Assad also denied US, British and French claims that his forces had used chemical weapons against his people during the escalating conflict in Syria.

"If Paris, London and Washington had any evidence for their claims, they would have submitted it to the global public," said Assad, whose comments were published in German.

"Everything that is being said about the use of chemical weapons is a continuation of the lies about Syria," he added. "It is the attempt to justify more military interference."

Assad added that the charges that his forces had used chemical weapons made no sense if the alleged death toll from their use was 150 people.

"Weapons of mass destruction are capable of killing hundreds or thousands at once. That's why they are used," Assad said.

"It is therefore illogical to use chemical weapons to kill numbers of people that could be achieved with the use of conventional weapons."

The conflict in Syria was set to dominate a G8 summit starting in Northern Ireland on Monday, with the Assad regime's ally Moscow expected to come under pressure from western powers.

Washington said last week it would provide Syria's rebels with military support after it determined that the regime had used chemical weapons.

Both London and Paris have discussed the possibility of sending weapons to the fighters that are battling the Syrian government, after the EU lifted an arms embargo.

Assad labelled the insurgents as terrorists and denied any blame for the escalation of the conflict, while defending cooperation with Russia and Iran as legitimate support.

He accused countries backing the rebels, also including Saudi Arabia, Qatar and Turkey, of "a blatant violation of international law and the sovereignty of the country" that aims to destabilise Syria and "create chaos and backwardness".

He accused former colonial powers Britain and France of seeking "lackeys and puppets" in the region but warned that destabilising Syria would cause regional turmoil.

"Every time one tinkers with the borders in the region, it means the map is redrawn. This has a domino effect that no one can control."